Multigap Superconductivity in GdFeAsO${}_{0.88}$ Evidenced by SnS-Andreev Spectroscopy

Abstract

Using intrinsic multiple Andreev reflection effect (IMARE) spectroscopy we studied superconducting properties of nearly optimal oxygen-deficient GdFeAsO${}_{0.88}$ polycrystalline samples (bulk critical temperatures $T_C^{bulk}=49÷52$\,K). Temperature dependences for two superconducting gaps ${\Delta }_{L,S}(T)$ ($T_C^{local}=48÷50$\,K) have been measured in the range from 4.2 to 50\,K. The ${\Delta }_{L,S}(T)$ dependences were found to deviate from the BCS-like function; this suggests an importance of the $k$-space (internal) proximity effect between the two condensates.

4 pages, 3 figures. Submitted to J. Supercond. Novel Magn. (Superstripes 2012 Proceedings)

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Cited by in corpus (5)

• Break-junction technique in application to layered superconductors (Review article)
• Lower critical field and SNS-Andreev spectroscopy of 122-arsenides: Evidence of nodeless superconducting gap
• Andreev spectroscopy of iron-based superconductors: temperature dependence of the order parameters and scaling of the ${\Delta }_{L,S}$ with $T_C$
• Estimation of intraband and interband relative coupling constants from temperature dependences of the order parameter for two-gap superconductors
• Intrinsic Multiple Andreev Reflections in layered Th-doped Sm${}_{1-x}$Th${}_x$OFeAs